It has long been the practice in the art to prepare acidified dairy products as, for example, cottage cheese, by inoculating bovine milk with mixed cultures of lactic acid-forming bacteria which ferment the milk until the desired acidity is achieved. Dairy products obtained commercially by this process are known as cultured products. The word "cultured" is used generically to describe any dairy product acidified by a process involving the use of bacteria in one of the processing steps. Preparing dairy products using bacterial cultures has oftentimes provided unsatisfactory results, however, in that the products can vary in quality and shelf life from day to day. Further, due to the long time period required for the fermentation, bacterial culture processes are not adaptable either to continuous operation or to automation techniques.
Various processes for preparing cheese from chemically acidified milk without using bacterial fermentation have more recently become known and practiced in the art. For example, U.S. Pat. Nos. 2,982,654 (Hammond et al.); 3,172,767 (Foster et al.); 3,406,076 (Little); 3,620,768 (Corbin); and 3,882,250 (Loter et al.) teach processes for making cheese curd at varying temperatures, employing various acidogens with or without further addition of proteolytic enzymes. Soybean curd, commonly known as "tofu," is an economical high protein food free of cholesterol and low in saturated fatty acids. It has long been prepared by extracting the juice (or milk) from soybeans, then coagulating the protein in the milk by addition of a coagulant. Many chemicals traditionally have been used as coagulants, for example, calcium sulfate, calcium chloride, magnesium chloride, ferric chloride, sodium bisulfate, and acetic acid (vinegar) or other edible acids. The most widely used of these coagulants traditionally has been calcium sulfate.
Finally, it has long been known to prepare raised bakery products, e.g., bread cake, biscuits and the like, both by the use of yeast or by chemicals evolving CO.sub.2 as leavening agents.